Front substrate of plasma display panel and fabricating method thereof

ABSTRACT

Disclosed is a front substrate of a plasma display panel and fabricating method thereof, by which color temperature, color purity, and contrast of PDP are enhanced. The present invention includes an upper dielectric layer containing a colorant therein. And, the present invention includes the step of forming an upper dielectric layer having a colorant added thereto.

This application is a Divisional of U.S. patent application Ser. No.10/747,211, filed Dec. 30, 2003. The entire disclosure of the priorapplication is considered as being part of the disclosure of theaccompanying application and is hereby incorporated by referencetherein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plasma display panel (hereinafterabbreviated PDP), and more particularly, to a front substrate of aplasma display panel and fabricating method thereof.

2. Description of the Background Art

Lately, a next generation multimedia display device plays a greatimportant role as a visual information transfer means according todevelopment and popularization of information processing systems.Specifically, as CRT (cathode ray tube) is inappropriate for the recenttarget of providing a large-sized and planarized screen, many effortsare made to study and develop such a flat panel display as LCD (liquidcrystal display), FED (field emission display), PDP, ELD(electroluminescent display), etc.

The PDP is a self-emission display device using plasma gas discharge,and has such various advantages as facilitation of size increment,excellent image quality, and fast video response speed. Moreover, thePDP as well as LCD is used as a wall-hanging display. A discharge cellof a three electrode AC surface discharge type PDP is explained byreferring to FIG. 1 as follows.

FIG. 1 is a cross-sectional view of a discharge cell of a threeelectrode AC surface discharge type PDP according to a related art.

Referring to FIG. 1, a discharge cell of the PDP is formed by combininga front substrate 110 and a back substrate 120 and by injectingdischarge gas between the front and back substrates 110 and 120.

The front substrate 110 consists of an upper glass substrate 100, atransparent electrode 101 and bus electrode 102 formed on the upperglass substrate 100, an upper dielectric layer 103 formed on the upperglass substrate 100 including the transparent and bus electrodes 101 and102 formed thereon, and a protection layer 104 formed on the upperdielectric layer 103.

In this case, the upper dielectric layer 103 restricts plasma dischargecurrent and accumulates wall charges on plasma discharge.

The back substrate 120 consists of a lower glass substrate 109, anaddress electrode 108 formed on the lower glass substrate 109, a lowerdielectric layer 107 formed on the lower glass substrate 109 includingthe address electrode 108, a barrier rib 106 formed on the lowerdielectric layer 107, and a phosphor 105 formed on the lower dielectriclayer 107 and the barrier rib 106.

An operational principle of the related art PDP is explained as follows.

First of all, a discharge sustain voltage is applied to the transparentand bus electrodes 101 and 102 to accumulate electric charges on theupper dielectric layer 103, and a discharge starting voltage is appliedto the address electrode 108 so that the discharge gas injected in thedischarge cells of the PDP such as He, Ne, Xe, and the like is separatedinto electrons and ions to be in a plasma state.

The phosphor 105 is excited by UV-rays generated from the reunion of theelectrons and ions to emit visible rays that represent characters orgraphics. In doing so, the PDP uses Ne having a relatively heavy atomicweight as a major component of the discharge gas to prevent thermaldeformation, which is caused by collision of accelerated gas ions, ofthe phosphor or dielectric layer.

Yet, the discharged Ne gas radiates an orange visible ray (585 nm),thereby degrading color purity and contrast of the PDP.

To overcome such a problem, a color filter layer or a black stripe layeris added to the upper substrate of the PDP.

FIG. 2 is a cross-sectional view of a front substrate of PDP accordingto a related art.

Referring to FIG. 2, a front substrate of PDP according to a related artconsists of an upper glass substrate 100, a transparent electrode 101and bus electrode 102 formed on the upper glass substrate 100, an upperdielectric layer 103 formed on the upper glass substrate 100 includingthe transparent and bus electrodes 101 and 102 formed thereon, a colorfilter layer 103A formed on the upper dielectric layer 103A, and aprotection layer 104 formed on the color filter layer 103A. In thiscase, the color filter layer 103A enables to adjust opticaltransmittance and to prevent surface reflection by an external light.

The above-constructed PDP according to the related art controls theoptical transmittance of a color filter by the color filter layer toenhance the color purity of the PDP and prevents the surface reflectionby the external light to enhance the contrast of the PDP.

However, the related art PDP needs to form the color filter layer on theupper dielectric layer, whereby a fabricating method thereof becomescomplicated.

Moreover, in the related art PDP, the optical transmittance of a bluevisible ray B is lower than that of a red or green visible ray R or G,whereby a color temperature of the PDP is about 6,000K. In order tocompensate for the low color temperature, an input signal correspondingto R, G, or B is adjusted, barrier ribs are formed asymmetrical, oroptical transmittance or dye of the color filter layer is adjusted. Yet,by adopting such a compensation, brightness of the PDP is reduceddespite the compensation for the color temperature.

On the other hand, the color filter layer can be replaced by the blackstripe layer. Yet, an aperture plane of the black stripe layer is small,whereby emission efficiency of the PDP is reduced.

As mentioned in the foregoing explanation, the related art PDP needs toform the color filter layer on the upper dielectric layer, whereby thefabricating method thereof becomes complicated.

Moreover, the optical transmittance of the blue visible ray B is lowerthan that of the red or green visible ray R or G, whereby the colortemperature of the PDP is low.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a front substrate of aplasma display panel and fabricating method thereof that substantiallyobviates one or more problems due to limitations and disadvantages ofthe related art.

An object of the present invention is to provide a front substrate of aplasma display panel and fabricating method thereof, by which a colortemperature of PDP is enhanced by forming an upper dielectric layercontaining a colorant amounting to a predetermined ratio for adjustingoptical transmittance.

Another object of the present invention is to provide a front substrateof a plasma display panel and fabricating method thereof, by which acolor purity of PDP is enhanced by forming an upper dielectric layercontaining a colorant amounting to a predetermined ratio for adjustingoptical transmittance.

Another object of the present invention is to provide a front substrateof a plasma display panel and fabricating method thereof, by which acontrast of PDP is enhanced by forming an upper dielectric layercontaining a colorant amounting to a predetermined ratio for adjustingoptical transmittance.

Another object of the present invention is to provide a front substrateof a plasma display panel and fabricating method thereof, by which PDPfabrication is simplified by forming an upper dielectric layercontaining a colorant amounting to a predetermined ratio for adjustingoptical transmittance.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, afront substrate of a plasma display panel according to the presentinvention includes an upper dielectric layer containing a colorantamounting to a predetermined ratio.

In another aspect of the present invention, a method of fabricating afront substrate of a plasma display panel including the step of formingan upper dielectric layer to which a colorant is added as much as apredetermined ratio.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a cross-sectional view of a discharge cell of a threeelectrode AC surface discharge type PDP according to a related art;

FIG. 2 is a cross-sectional view of a front substrate of PDP accordingto a related art;

FIG. 3 is a cross-sectional view of a front substrate of PDP accordingto the present invention;

FIG. 4 is a flowchart of a method of fabricating a front substrate ofPDP according to the present invention;

FIG. 5 is a flowchart of forming an upper dielectric layer in FIG. 3;and

FIG. 6 is a graph of experimental optical transmittance of PDP accordingto the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

FIG. 3 is a cross-sectional view of a front substrate of PDP accordingto the present invention.

Referring to FIG. 3, a front substrate of PDP according to the presentinvention includes an upper glass substrate 100, a transparent electrode101 and bus electrode 102 formed on the upper glass substrate 100, acolorant-added upper dielectric layer 103B formed on the upper glasssubstrate 100 including the transparent and bus electrodes 101 and 102formed thereon, and a protection layer 104 formed on the upperdielectric layer 103.

A method of fabricating the above-constructed front substrate accordingto the present invention is explained by referring to FIG. 4 as follows.

FIG. 4 is a flowchart of a method of fabricating a front substrate ofPDP according to the present invention.

Referring to FIG. 4, a method of fabricating a front substrate of PDPaccording to the present invention includes the steps of forming anupper glass substrate (S41), forming a transparent electrode 101 and buselectrode 102 on the upper glass substrate 100 (S42), forming an upperdielectric layer 103B, to which a colorant amounting to a predeterminedratio is previously added, on the upper glass substrate 100 includingthe transparent and bus electrodes 101 and 102 formed thereon (S43), andforming a protection layer 104 on the upper dielectric layer 103 (S44).

The method of fabricating the front substrate of PDP according to thepresent invention is explained in detail as follows.

First of all, after the upper substrate 100 has been prepared (S41), thetransparent and bus electrodes 101 and 102 are formed on the upper glasssubstrate 100 (S42).

The upper dielectric layer 103B, to which a colorant amounting to apredetermined ratio is previously added, is then formed on the upperglass substrate 100 including the transparent and bus electrodes 101 and102 formed thereon. A method of forming the upper dielectric layer ofthe PDP is explained by referring to FIG. 5 as follows.

FIG. 5 is a flowchart of forming the upper dielectric layer in FIG. 3.

Referring to FIG. 5, a method of forming the upper dielectric layer ofthe PDP according to the present invention includes the steps of formingglass powder to which the colorant amounting to the predetermined ratiois added (S51), forming a dielectric paste by mixing the glass powder, abinder, and a solvent with each other (S52), forming a dielectric pastelayer by coating a front surface of the upper glass substrate, on whichthe transparent and bus electrodes are formed, with the dielectric paste(S53), and plasticizing the dielectric paste layer to form the upperdielectric layer (S54).

The method of forming the upper dielectric layer of the PDP according tothe present invention is explained in detail as follows.

First of all, the colorant for adjusting an optical transmittance ismixed with a parent glass as much as the predetermined ratio to preparea glass. The prepared glass is then pulverized to form the glass powderhaving a predetermined particle size each (S51). In this case, thepredetermined particle ratio is a weight ratio of the colorant vs. themother parent. Preferably, the predetermined ratio is equal to orsmaller than 5 wt % and the predetermined particle size lies 1˜5 μm.

The mother glass includes the components shown in one of Table 1(PbO—B₂O₃—SiO₂—Al₂O₃—BaO based glass), Table 2 (P₂O₅—B₂O₃—ZnO basedglass), and Table 3 (ZnO—B₂O₃—RO based glass). In this case, eachcomponent unit is wt % (weight %). TABLE 1 PbO wt % B₂O₃ wt % SiO₂ +Al₂O₃ wt % BaO wt % 35.0 35.0 20.0 10.0 40.0 30.5 15.0 14.5 45.0 25.010.0 20.0 50.0 27.0 5.0 18.0 60.0 30.0 0.0 10.0

TABLE 2 B₂O₃ wt % ZnO wt % P₂O₅ wt % 0.0 46.2 53.8 3.3 44.7 52.0 6.843.1 50.1 10.4 41.4 48.2 14.1 39.7 46.2 18.0 37.9 44.1 22.0 36.1 41.9

TABLE 3 ZnO wt % B₂O₃ wt % RO wt % 19.8 42.4 37.8 24.6 37.9 37.5 29.333.4 37.3 34.0 29.0 37.0

RO as a component of the mother glass in Table 3 is selected from thegroup consisting of BaO, SrO, La₂O, Bi₂O₃, MgO, and ZnO. Preferably, asubstance used as the colorant is at least one of CuO, CoO, Nd₂O₃, NiO,Cr₂O₃, Pr₂O₃, and Fe₂O₃.

After forming the glass powder including the mother glass and thecolorant, the glass powder and ethylcellulose binder are mixed in thesolvent dissolving the binder such as α-terpineol, BCA (butyl cabitolacetate), BC (butyl cabitol), and TX (texanol) to form the dielectricpaste (S52).

The dielectric paste is coated on the upper glass substrate having thetransparent and bus electrodes formed thereon by screen-printing orthick film coating to form the dielectric paste layer (S53).

The dielectric paste layer is plasticized for 10˜30 minutes at 550˜600°C. to form the upper dielectric layer of the PDP (S54).

Thereafter, the protection layer is formed on the upper dielectric layerto complete the front substrate of the PDP. An experimental result ofoptical transmittance of PDP according to the present invention isexplained by referring to FIG. 6 as follows.

FIG. 6 is a graph of experimental optical transmittance of PDP accordingto the present invention.

Referring to FIG. 6, optical transmittance of a blue visible ray (454nm)B is higher than that of a red or green visible ray (611 nm or 525nm) R or G. It is expected that color temperature, color purity, andcontrast of the PDP will be remarkably enhanced according to the testresult. In this case, it is expected that the color temperature of thePDP is enhanced over about 1,000K.

Accordingly, the front substrate of the PDP and fabricating methodthereof according to the present invention has the following advantagesor effects.

First of all, the colorant amounting to the predetermined ratio is addedto the upper dielectric layer to adjust the optical transmittance,whereby the color impurity of the PDP is enhanced.

Secondly, the colorant amounting to the predetermined ratio is added tothe upper dielectric layer to adjust the optical transmittance, wherebythe color temperature of the PDP is enhanced.

Thirdly, the colorant amounting to the predetermined ratio is added tothe upper dielectric layer to adjust the optical transmittance, wherebythe optical transmittance of the blue visible ray B is increased toenhance the contrast of the PDP.

Finally, the colorant amounting to the predetermined ratio is added tothe upper dielectric layer to adjust the optical transmittance, wherebyan additional filter layer needs not to be formed to simplify thefabricating method of the PDP.

The forgoing embodiments are merely exemplary and are not to beconstrued as limiting the present invention. The present teachings canbe readily applied to other types of apparatuses. The description of thepresent invention is intended to be illustrative, and not to limit thescope of the claims. Many alternatives, modifications, and variationswill be apparent to those skilled in the art.

1. A method of fabricating a front substrate of a plasma display panelincluding the step of forming an upper dielectric layer having acolorant added thereto.
 2. The method of claim 1, wherein the colorantis a substance for adjusting optical transmittance.
 3. The method ofclaim 2, wherein the colorant is selected from the group consisting ofCuO, CoO, Nd₂O₃, NiO, Cr₂O₃, Pr₂O₃, and Fe₂O₃.
 4. The method of claim 1,wherein the colorant is added below 5 wt %.
 5. The method of claim 1,the step of forming the upper dielectric layer comprising the steps of:forming glass powder to which the colorant amounting to a predeterminedratio is added; forming a dielectric paste by mixing the glass powder, abinder, and a solvent; forming a dielectric paste layer by coating afront surface of an upper glass substrate having transparent and buselectrodes formed thereon with the dielectric paste; and plasticizingthe dielectric paste layer.
 6. The method of claim 5, the step offorming the glass powder, comprising the steps of: preparing a glass bymixing a mother glass and the colorant; and pulverizing the preparedglass.
 7. The method of claim 6, wherein the mother glass is selectedfrom the group consisting of PbO—B₂O₃—SiO₂—Al₂O₃—BaO based glass,P₂O₅—B₂O₃—ZnO based glass, and ZnO—B₂O₃—RO based glass.
 8. The method ofclaim 5, wherein the colorant is a substance for adjusting opticaltransmittance.
 9. The method of claim 8, wherein the colorant isselected from the group consisting of CuO, CoO, Nd₂O₃, NiO, Cr₂O₃,Pr₂O₃, and Fe₂O₃.
 10. The method of claim 5, wherein the colorant isadded below 5 wt %.
 11. The method of claim 6, wherein the preparedglass is pulverized by particle size of 1˜5 μm.
 12. The method of claim5, wherein the dielectric paste layer is plasticized for 10˜30 minutesat 550˜600° C.